Quilting is a special art in the general field of sewing in which patterns are stitched through a plurality of layers of material over a two dimensional area of the material. The multiple layers of material normally include at least three layers, one a woven primary or facing sheet having a decorative finished quality, one a usually woven backing sheet that may or may not be of a finished quality, and one or more internal layers of thick filler material, usually of randomly oriented fibers. The stitched patterns maintain the physical relationship of the layers of material to each other as well as provide ornamental qualities. Quilting is performed on the customary quilts or comforters and on the covers of mattresses, for example. In the stitching of quilts for these two applications, two different approaches are typically used. Both approaches use stitches that employ both a top and a bottom thread.
Single needle quilters of the type illustrated and described in U.S. Pat. Nos. 5,640,916 and 5,685,250, hereby expressly incorporated by reference herein, are customarily used for the stitching of comforters and other preformed rectangular panels. Such single needle quilters typically use a pair of cooperating lock stitch sewing heads, one carrying a needle drive that is typically positioned above the fabric and one carrying a bobbin that is opposite the fabric from the needle, with both heads being mechanically linked to move together in two dimensions, relative to the panel, parallel to the plane of the panel. A common operation of this type of quilting apparatus includes the supporting of the panel of fabric on a longitudinally moveable shuttle with the sewing heads moveable transversely of the panel to provide two dimensional stitching capability of the pattern on the panel. With such single needle quilting machines, varied and complex patterns can be produced.
Multiple needle quilters of the type illustrated in U.S. Pat. Nos. 5,154,130 and 5,554,589, hereby expressly incorporated by reference herein, are customarily used for the stitching of mattress covers, which are commonly formed from multi-layered web fed material. Such multi-needle quilters use an array of cooperating chain stitch sewing elements, one element being a needle that is typically positioned above the material and one element being a looper that is opposite the material from the needle, with the entire arrays of both elements being mechanically linked together to move in unison in two dimensions relative to the material, parallel to the plane of the material in paths that corresponds to identical patterns of a pattern array. The needles and loopers also operate in unison so that the sets of elements simultaneously form identical series of stitches.
A common operation of this type of quilting apparatus is to support the multilayered material from a web and advance the web longitudinally relative to the sewing element array and in coordination with the motion and operation of the sewing elements. The sewing element array may be shiftable transversely of the web to provide two dimensional movement of the array relative to the material to give pattern stitching capability on the web. Alternatively, the array may be also maintained stationary in the transverse direction and rollers that support the web may be caused shift transversely relative to the array to move the web relative to the sewing elements. Some multi-needle quilters of this type have longitudinally bi-directional web feeding capability which, when synchronized with the transverse shifting of the web or the sewing elements, provides for 360.degree. pattern sewing capability.
The multi-needle quilters are preferable for sewing mattress covers and for other applications where high speed production is required. With these multi-needle web-fed quilting machines, however, the variety and complexity of patterns is limited.